https://github.com/oracle/graal: GraalVM is an ecosystem for compiling and running applications written in multiple languages. GraalVM removes the isolation between programming languages and enables interoperability in a shared runtime. 
public final class org.graalvm.nativeimage.hosted.RuntimeClassInitialization
  minor version: 0
  major version: 59
  flags: flags: (0x0031) ACC_PUBLIC, ACC_FINAL, ACC_SUPER
  this_class: org.graalvm.nativeimage.hosted.RuntimeClassInitialization
  super_class: java.lang.Object
{
  private static final java.lang.String MESSAGE;
    descriptor: Ljava/lang/String;
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: "from feature "

  public static void initializeAtRunTime(java.lang.Class<?>[]);
    descriptor: ([Ljava/lang/Class;)V
    flags: (0x0089) ACC_PUBLIC, ACC_STATIC, ACC_VARARGS
    Code:
      stack=5, locals=6, args_size=1
        start local 0 // java.lang.Class[] classes
         0: .line 97
            invokestatic java.lang.Thread.currentThread:()Ljava/lang/Thread;
            invokevirtual java.lang.Thread.getStackTrace:()[Ljava/lang/StackTraceElement;
            astore 1 /* stacktrace */
        start local 1 // java.lang.StackTraceElement[] stacktrace
         1: .line 98
            aload 0 /* classes */
            dup
            astore 5
            arraylength
            istore 4
            iconst_0
            istore 3
            goto 5
      StackMap locals: java.lang.Class[] java.lang.StackTraceElement[] top int int java.lang.Class[]
      StackMap stack:
         2: aload 5
            iload 3
            aaload
            astore 2 /* aClass */
        start local 2 // java.lang.Class aClass
         3: .line 99
            ldc Lorg/graalvm/nativeimage/impl/RuntimeClassInitializationSupport;
            invokestatic org.graalvm.nativeimage.ImageSingletons.lookup:(Ljava/lang/Class;)Ljava/lang/Object;
            checkcast org.graalvm.nativeimage.impl.RuntimeClassInitializationSupport
            aload 2 /* aClass */
            new java.lang.StringBuilder
            dup
            ldc "from feature "
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            aload 1 /* stacktrace */
            invokestatic org.graalvm.nativeimage.hosted.RuntimeClassInitialization.getCaller:([Ljava/lang/StackTraceElement;)Ljava/lang/String;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokeinterface org.graalvm.nativeimage.impl.RuntimeClassInitializationSupport.initializeAtRunTime:(Ljava/lang/Class;Ljava/lang/String;)V
        end local 2 // java.lang.Class aClass
         4: .line 98
            iinc 3 1
      StackMap locals:
      StackMap stack:
         5: iload 3
            iload 4
            if_icmplt 2
         6: .line 101
            return
        end local 1 // java.lang.StackTraceElement[] stacktrace
        end local 0 // java.lang.Class[] classes
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0    7     0     classes  [Ljava/lang/Class;
            1    7     1  stacktrace  [Ljava/lang/StackTraceElement;
            3    4     2      aClass  Ljava/lang/Class<*>;
    Signature: ([Ljava/lang/Class<*>;)V
    MethodParameters:
         Name  Flags
      classes  

  public static void initializeAtBuildTime(java.lang.Class<?>[]);
    descriptor: ([Ljava/lang/Class;)V
    flags: (0x0089) ACC_PUBLIC, ACC_STATIC, ACC_VARARGS
    Code:
      stack=5, locals=6, args_size=1
        start local 0 // java.lang.Class[] classes
         0: .line 116
            invokestatic java.lang.Thread.currentThread:()Ljava/lang/Thread;
            invokevirtual java.lang.Thread.getStackTrace:()[Ljava/lang/StackTraceElement;
            astore 1 /* stacktrace */
        start local 1 // java.lang.StackTraceElement[] stacktrace
         1: .line 117
            aload 0 /* classes */
            dup
            astore 5
            arraylength
            istore 4
            iconst_0
            istore 3
            goto 5
      StackMap locals: java.lang.Class[] java.lang.StackTraceElement[] top int int java.lang.Class[]
      StackMap stack:
         2: aload 5
            iload 3
            aaload
            astore 2 /* aClass */
        start local 2 // java.lang.Class aClass
         3: .line 118
            ldc Lorg/graalvm/nativeimage/impl/RuntimeClassInitializationSupport;
            invokestatic org.graalvm.nativeimage.ImageSingletons.lookup:(Ljava/lang/Class;)Ljava/lang/Object;
            checkcast org.graalvm.nativeimage.impl.RuntimeClassInitializationSupport
            aload 2 /* aClass */
            new java.lang.StringBuilder
            dup
            ldc "from feature "
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            aload 1 /* stacktrace */
            invokestatic org.graalvm.nativeimage.hosted.RuntimeClassInitialization.getCaller:([Ljava/lang/StackTraceElement;)Ljava/lang/String;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokeinterface org.graalvm.nativeimage.impl.RuntimeClassInitializationSupport.initializeAtBuildTime:(Ljava/lang/Class;Ljava/lang/String;)V
        end local 2 // java.lang.Class aClass
         4: .line 117
            iinc 3 1
      StackMap locals:
      StackMap stack:
         5: iload 3
            iload 4
            if_icmplt 2
         6: .line 120
            return
        end local 1 // java.lang.StackTraceElement[] stacktrace
        end local 0 // java.lang.Class[] classes
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0    7     0     classes  [Ljava/lang/Class;
            1    7     1  stacktrace  [Ljava/lang/StackTraceElement;
            3    4     2      aClass  Ljava/lang/Class<*>;
    Signature: ([Ljava/lang/Class<*>;)V
    MethodParameters:
         Name  Flags
      classes  

  public static void initializeAtRunTime(java.lang.String[]);
    descriptor: ([Ljava/lang/String;)V
    flags: (0x0089) ACC_PUBLIC, ACC_STATIC, ACC_VARARGS
    Code:
      stack=5, locals=6, args_size=1
        start local 0 // java.lang.String[] packages
         0: .line 136
            invokestatic java.lang.Thread.currentThread:()Ljava/lang/Thread;
            invokevirtual java.lang.Thread.getStackTrace:()[Ljava/lang/StackTraceElement;
            astore 1 /* stacktrace */
        start local 1 // java.lang.StackTraceElement[] stacktrace
         1: .line 137
            aload 0 /* packages */
            dup
            astore 5
            arraylength
            istore 4
            iconst_0
            istore 3
            goto 5
      StackMap locals: java.lang.String[] java.lang.StackTraceElement[] top int int java.lang.String[]
      StackMap stack:
         2: aload 5
            iload 3
            aaload
            astore 2 /* aPackage */
        start local 2 // java.lang.String aPackage
         3: .line 138
            ldc Lorg/graalvm/nativeimage/impl/RuntimeClassInitializationSupport;
            invokestatic org.graalvm.nativeimage.ImageSingletons.lookup:(Ljava/lang/Class;)Ljava/lang/Object;
            checkcast org.graalvm.nativeimage.impl.RuntimeClassInitializationSupport
            aload 2 /* aPackage */
            new java.lang.StringBuilder
            dup
            ldc "from feature "
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            aload 1 /* stacktrace */
            invokestatic org.graalvm.nativeimage.hosted.RuntimeClassInitialization.getCaller:([Ljava/lang/StackTraceElement;)Ljava/lang/String;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokeinterface org.graalvm.nativeimage.impl.RuntimeClassInitializationSupport.initializeAtRunTime:(Ljava/lang/String;Ljava/lang/String;)V
        end local 2 // java.lang.String aPackage
         4: .line 137
            iinc 3 1
      StackMap locals:
      StackMap stack:
         5: iload 3
            iload 4
            if_icmplt 2
         6: .line 140
            return
        end local 1 // java.lang.StackTraceElement[] stacktrace
        end local 0 // java.lang.String[] packages
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0    7     0    packages  [Ljava/lang/String;
            1    7     1  stacktrace  [Ljava/lang/StackTraceElement;
            3    4     2    aPackage  Ljava/lang/String;
    MethodParameters:
          Name  Flags
      packages  

  public static void initializeAtBuildTime(java.lang.String[]);
    descriptor: ([Ljava/lang/String;)V
    flags: (0x0089) ACC_PUBLIC, ACC_STATIC, ACC_VARARGS
    Code:
      stack=5, locals=6, args_size=1
        start local 0 // java.lang.String[] packages
         0: .line 155
            invokestatic java.lang.Thread.currentThread:()Ljava/lang/Thread;
            invokevirtual java.lang.Thread.getStackTrace:()[Ljava/lang/StackTraceElement;
            astore 1 /* stacktrace */
        start local 1 // java.lang.StackTraceElement[] stacktrace
         1: .line 156
            aload 0 /* packages */
            dup
            astore 5
            arraylength
            istore 4
            iconst_0
            istore 3
            goto 5
      StackMap locals: java.lang.String[] java.lang.StackTraceElement[] top int int java.lang.String[]
      StackMap stack:
         2: aload 5
            iload 3
            aaload
            astore 2 /* aPackage */
        start local 2 // java.lang.String aPackage
         3: .line 157
            ldc Lorg/graalvm/nativeimage/impl/RuntimeClassInitializationSupport;
            invokestatic org.graalvm.nativeimage.ImageSingletons.lookup:(Ljava/lang/Class;)Ljava/lang/Object;
            checkcast org.graalvm.nativeimage.impl.RuntimeClassInitializationSupport
            aload 2 /* aPackage */
            new java.lang.StringBuilder
            dup
            ldc "from feature "
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            aload 1 /* stacktrace */
            invokestatic org.graalvm.nativeimage.hosted.RuntimeClassInitialization.getCaller:([Ljava/lang/StackTraceElement;)Ljava/lang/String;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokeinterface org.graalvm.nativeimage.impl.RuntimeClassInitializationSupport.initializeAtBuildTime:(Ljava/lang/String;Ljava/lang/String;)V
        end local 2 // java.lang.String aPackage
         4: .line 156
            iinc 3 1
      StackMap locals:
      StackMap stack:
         5: iload 3
            iload 4
            if_icmplt 2
         6: .line 159
            return
        end local 1 // java.lang.StackTraceElement[] stacktrace
        end local 0 // java.lang.String[] packages
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0    7     0    packages  [Ljava/lang/String;
            1    7     1  stacktrace  [Ljava/lang/StackTraceElement;
            3    4     2    aPackage  Ljava/lang/String;
    MethodParameters:
          Name  Flags
      packages  

  private static java.lang.String getCaller(java.lang.StackTraceElement[]);
    descriptor: ([Ljava/lang/StackTraceElement;)Ljava/lang/String;
    flags: (0x000a) ACC_PRIVATE, ACC_STATIC
    Code:
      stack=3, locals=2, args_size=1
        start local 0 // java.lang.StackTraceElement[] stackTrace
         0: .line 162
            aload 0 /* stackTrace */
            iconst_2
            aaload
            astore 1 /* e */
        start local 1 // java.lang.StackTraceElement e
         1: .line 163
            new java.lang.StringBuilder
            dup
            aload 1 /* e */
            invokevirtual java.lang.StackTraceElement.getClassName:()Ljava/lang/String;
            invokestatic java.lang.String.valueOf:(Ljava/lang/Object;)Ljava/lang/String;
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            ldc "."
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            aload 1 /* e */
            invokevirtual java.lang.StackTraceElement.getMethodName:()Ljava/lang/String;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            areturn
        end local 1 // java.lang.StackTraceElement e
        end local 0 // java.lang.StackTraceElement[] stackTrace
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0    2     0  stackTrace  [Ljava/lang/StackTraceElement;
            1    2     1           e  Ljava/lang/StackTraceElement;
    MethodParameters:
            Name  Flags
      stackTrace  

  private void <init>();
    descriptor: ()V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.graalvm.nativeimage.hosted.RuntimeClassInitialization this
         0: .line 168
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 169
            return
        end local 0 // org.graalvm.nativeimage.hosted.RuntimeClassInitialization this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lorg/graalvm/nativeimage/hosted/RuntimeClassInitialization;
}
SourceFile: "RuntimeClassInitialization.java"
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.Platforms(value = {Lorg/graalvm/nativeimage/Platform$HOSTED_ONLY;})